The present invention relates to the processing of, and metals recovery from, used electrical equipment such as transformers. More particularly, the invention provides an environmentally safe process for the disposal and recycling of contaminated oil-containing electrical equipment by incinerating the equipment in intact form in order to destroy the oil and its contaminants, thus rendering the equipment suitable for metal recycling and recovery. Advantageously, the process is carried out without workers being exposed to the contaminated oil.
Each year, millions of pieces of electrical equipment become outmoded and must be discarded by power companies and other industries. One challenge facing the electrical equipment industry is the disposal of such equipment in a manner consistent with governmental regulations and, beyond the letter of the applicable regulations, sound environmental protection practices regarding the disposal of hazardous materials.
Electrical equipment such as transformers used throughout electric power supply systems are known to contain insulating (dielectric) oil, insulation and other combustible materials containing a variety of harmful substances such as polychlorinated biphenyls ("PCB's"), dioxin and furans. The harmful effects of PCB's and many other oil contaminants have been well documented in recent years, and government regulations address the disposal of such contaminant-laden oil.
A prior method employed for the de-commissioning and disposal of electrical transformers containing contaminated insulating oil starts with draining the oil from the transformer tank enclosure, followed by disassembly of the transformer and its components from the tank. The various components, which are manufactured from silicon steel, copper, aluminum, ceramic and possibly other materials are stacked in a furnace and burned. The tank enclosures, which continue to contain residual amounts of contaminated dielectric oil, are either rinsed with a solvent or filled with an absorbent material. The oil-laden solvent or absorbent then is discarded, frequently without regard for its harmful contents.
In addition to problems related to the disposal of the solvent or absorbent, the process suffers from the disadvantage that workers are exposed to the contaminated oil, insulation and other materials. Also, burning transformer coils which have been removed from their cases has resulted in an uncontrollable burn, with the final temperature reaching 1600.degree. F. The uncontrollable burn caused a complete meltdown of the aluminum and produced a lake of melted aluminum on the furnace floor. Thus, this process would not be suited for the commercial processing and disposal of spent electrical equipment and metals recovery therefrom.
One object of the present invention is to provide an environmentally safe process for recycling spent electrical equipment which permits total destruction of contaminated combustible material from the equipment, and recycling of 100 percent of the non-combustible materials, thus totally eliminating the need for landfill or scrap yard storage of spent electrical equipment.
Another object of this invention is to provide such a process which employs only environmentally sound practices for the destruction of contaminant-containing insulating oil, insulation and other combustible materials, and avoids the use of chemicals, solvents, absorbents or other materials which themselves present disposal hazards.
A further object of this invention is to reduce potential financial liability of the electrical equipment owner by eliminating the possibility of contaminated oil-related health problems among its employees, the environment and the public at large.